Reference Levels in the Context of Fukushima and Related Lessons Learned

Abstract

About 1 mo after the Fukushima Dai-ichi nuclear power plant accident, which was caused by the Great East Japan earthquake and tsunami on 11 March 2011, Japanese authorities set a dose criterion for the use of school playgrounds in Fukushima at 20 mSv y⁻¹ based on the International Commission on Radiological Protection recommendation for the reference level for the public under the existing exposure situation. This dose criterion was intended as a start line for reducing the dose to children; however, it caused much confusion among the public due to the misunderstanding of the concept of optimization and the application of reference level. Also, concerns were caused by the lack of precise but understandable information on radiation effects. This situation highlighted the importance of an understanding of radiation protection concepts by members of the general public and the outreach activities of radiation protection experts, both of which are essential for Fukushima recovery.